Previous research has established that the ability to manage emotions effectively is critical to healthy psychological and social development in adolescents. However, less research has considered the relationships between specific emotion regulation (ER) strategies, such as reappraisal and suppression, and social wellbeing in this age group. The current study investigated the concurrent and longitudinal relationships between 2 ER strategies (reappraisal and suppression) and social outcomes (peer victimization, friendship satisfaction, and family satisfaction) in young adolescents. Analyses also controlled for mental health (anxiety and depression). Given likely gender differences in these variables, key analyses were conducted in parallel for males and females. There were 232 Australian adolescents who completed measures in Grade 7 (Age Mean = 11.97, SD = .35; 64% female) and a year later in Grade 8. Zero-order correlations indicated an inverse relationship between suppression use and social wellbeing variables, although a number of these associations were no longer significant when controlling for mental health. There was limited evidence that reappraisal was uniquely related to social outcomes. However, interaction effects suggested that greater use of reappraisal might have provided some protection against the negative social effects of poorer mental health. Poorer mental and social wellbeing also appeared to be related to ER strategy use, particularly greater suppression use. The findings suggest that ER strategy use, mental health, and social outcomes all play important and interrelated roles in adolescent wellbeing.